add notice about providing name of openstack instance

topics/compute/openstack/docs/technical-reference/ostrava-site/get-support.md

@@ -7,7 +7,7 @@ search:
 
 # Get Support
 
-Contact points are listed in the following table. 
+Contact points are listed in the following table. Please provide name of instance of openstack you are using e.g. ostrava.openstack.cloud.e-infra.cz
 
 | Point                    | Contact                                                        |
 |--------------------------|----------------------------------------------------------------|